Braiding or stranding machine

ABSTRACT

A braiding or stranding machine for braiding or stranding a strand-like material is disclosed. In one aspect, the machine includes a rotor with a one-part or a multi-part rotor shaft which is driven by at least one motor, the braiding or stranding machine being at least partially arranged in a sealed space which is filled with a medium with a lower density than the density of the ambient air. The rotor shaft is completely arranged within an enclosure of the sealed space. Alternatively, the rotor shaft has at least one section of a smaller diameter and at least one section of a larger diameter and penetrates the enclosure of the sealed space only in the at least one section of the smaller diameter.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application, and claims the benefit under 35 U.S.C. §§120 and 365 of PCT Application No. PCT/EP2013/003711, filed on Dec. 9, 2013, which is hereby incorporated by reference. PCT/EP2013/003711 also claimed priority from German Patent Application No. 10 2012 024 232.8 filed on Dec. 11, 2012, which is hereby incorporated by reference.

BACKGROUND

1. Field

The described technology generally relates to a braiding or stranding machine for braiding or stranding a strand-like material.

2. Description of the Related Technology

Here, the strand-like material can, for example, be a metallic material like a copper, steel, or aluminum wire or a metallic conductor with different alloy components or a non-metallic material like a natural or synthetic fiber, in which case several strands of such a fiber are braided, i.e., processed to a braid, by twisting them with each other. However, the strand-like material can also be, for instance, such a braid, in which case several strands of such a braid are likewise stranded, i.e., processed to a cable or a rope, by twisting them with each other.

In a braiding machine of the type presently considered, braiding is done by means of a revolving rotor which usually has one or more rotor bows which are supported at both of their axial ends on a one-part or multi-part rotor shaft. The rotor is fed with at least two strands of the strand-like material (of the same type or of different types), and the strands are guided over a rotor bow, resulting in the strands being twisted. The braid manufactured in this way is then led away again from the rotor bow.

Both the strand-like material to be braided and the braid manufactured therefrom are fed to the braiding machine on spools or are wound onto a spool, respectively. In order to achieve different forms of the twisting of the strand-like material, the spools for the strand-like material or the spool for the manufactured braid can either stand still or can rotate with the same rotational frequency and in the same direction as the rotor. Here, the spools can be arranged inside the braiding machine, for example, between the axial ends of the rotor, or outside the braiding machine. By a suitable arrangement of the spools, so-called single-twist, double-twist or other multi-twist braiding machines can be realized.

With usual braiding machines, the rotor bow rotates with a high rotational frequency inside the ambient air, which is also present in the inner space of the machine. The rotor and possibly also the strand-like material—provided the latter is not guided in the interior of the rotor bow or in a pipe—therefore must continuously overcome the air resistance. The mechanical power needed therefor is, among other things, dependent on the density of the air and the linear velocity of the rotor bow, the power rising with the square of the velocity. Therefore, high braiding velocities and thus high rotational frequencies of the rotor bow also require correspondingly high power, which is converted to a large extent to frictional heat resulting from the air friction and must be discharged from the braiding machine with large effort. Thus, an increase of productivity is only achievable with large effort.

Another problem at high rotational frequencies are increased noise emissions and an increased vibrational excitation of the rotor bow having its reasons in that the flow-related boundary conditions between the rotor bow and adjacent machine components periodically change during the rotation of the rotor bow.

In order to avoid these problems, for example, the heat and noise generation, during the operation of a braiding machine, DE 22 41 826 proposes to carry out at least a part of the braiding process within a sealed space in which at least a partial vacuum has been generated. Due to the reduced air friction, less noise and less frictional heat is generated by the rotor bow in the partial vacuum. Likewise, the reduced air resistance leads to a reduced energy consumption of the braiding machine.

In this context, DE 22 41 826 proposes for economical reasons to arrange only certain parts of the braiding machine in a substantially hermetically sealed space from which air has been drawn off. In the example embodiments, the two outer sections or the rotor shaft together with the turning heads arranged thereon are supported in frontal openings of a cylindrical, air-tight housing, the air-tightness in these areas being established by annular air sealings.

Conventional annular air sealings used in the prior art which the shaft sections are sealed with against the housing and which have components contacting each other and rotating relative to each other, can get very hot at high rotational frequencies, which makes them wear more quickly and whereby also the operating personnel of the braiding machine is exposed to a risk of burns when touching the sealings. Moreover, the generated friction requires energy and is therefore not economical. “Frictionless” sealing systems, on the other hand, are complex and expensive.

Apart from this, the heat development caused by such an air sealing and the wear thereof increase with the diameter of the air sealing, as the peripheral velocity at the outer edge of the rotating component, thus the velocity of the components of the air sealing relative to each other and thus also the generated frictional heat increase in this way.

SUMMARY OF CERTAIN INVENTIVE ASPECTS

One inventive aspect relates to a braiding machine or a stranding machine.

Another aspect is a double-twist braiding machine with a single rotor bow, with the spools for the strand-like material being arranged outside the machine and standing still, and with the spool for the manufactured braid being supported inside the machine on the rotor and not rotating therewith. This is not a restriction either. The invention is also applicable to braiding machines with other arrangements of the spools and/or of the rotor bow.

Another aspect is an improved braiding machine with reduced energy consumption, reduced noise development and reduced vibrational excitation.

Another aspect is a braiding machine for braiding a strand-like material having a rotor with a single-part or multi-part rotor shaft which is driven by at least one motor, the braiding machine being arranged at least partially in a sealed space which is filled with a medium with a lower density than the density of the ambient air.

With such a braiding machine the rotor shaft is, according to some embodiments, completely arranged within the enclosure of the sealed space, or the rotor shaft has at least one section of smaller diameter and at least one section of larger diameter and penetrates the enclosure of the sealed space only in the at least one section of smaller diameter.

In this way, air sealings with components contacting each other and rotating against each other having large diameters and the high heat development resulting therefrom as well as the big wear of the air sealings during the operation of the braiding machine can be avoided.

In a braiding machine according to some embodiments, the rotor shaft therefore does not penetrate the sealed space at a point at which the rotor shaft has its largest diameter.

In some embodiments, the rotor shaft does not penetrate the enclosure of the sealed space at all. In this way, the problems mentioned with the air sealings are completely avoided at least with respect to the rotor shaft.

In some embodiments, the braiding machine does not have any sealings at all for sealing the sealed space against the environment with components contacting each other and rotating against each other. In this case, the problems mentioned with such sealings are completely avoided for the whole braiding machine.

In the following, several design measures are stated which can be taken for realizing these objectives:

In some embodiments, the rotor is rotationally driven only at one axial end thereof. In this way, a drive at the other axial end of the rotor, for example, a motor and/or a torque transmission device, is saved. The omission of a drive of the rotor at both ends becomes possible by the fact that the rotor bow can be designed with a larger cross-sectional area due to the decreased air resistance, without this resulting in a substantial increase of the energy consumption of the braiding machine. The rotational movement of the non-driven axial end of the rotor is then transmitted by the—correspondingly more stable—rotor bow itself

In some embodiments, the rotor has at least one rotor bow which is reinforced in the area of at least one of its axial ends compared to its middle section, for example, by an increase of its cross-sectional area. In this way, the rotor bow is intentionally reinforced in those areas in which it is loaded with the highest torque.

In some embodiments, the rotor has at least two rotor bows. This leads to a distribution of the torque arising during operation to several, for example, identically designed components. Here, the at least two rotor bows can be arranged in equal angular distances to each other with respect to the rotational axis to the rotor, i.e., if for instance exactly two rotor bows are provided, they face each other diametrically with respect to the rotational axis of the rotor. Due to the reduced air resistance, this does not lead to a substantial increase in the energy consumption of the braiding machine either.

In some embodiments, the rotor shaft is driven at both axial ends of the rotor by one motor each. In this way, a uniform drive of the whole rotor can be reached, without the two axial ends of the motor having to be connected by moving components.

In some embodiments, the rotor shaft is driven by exactly one motor, the motor being coupled with the two axial ends of the rotor by mechanical torque transmission means and the drive acting on both axial ends of the rotor shaft, the mechanical torque transmission means being completely or partially arranged inside the sealed space. In this way, a drive of the rotor shaft at the two axial ends thereof which is synchronized with respect to its rotational frequency can be reached by simple means. At the same time, due to the arrangement of the mechanical torque transmission means, one can completely or partially do without further air sealings with components contacting each other and rotating against each other, for example, such air sealings with large diameters.

In some embodiments, the mechanical torque transmission means have at least one tooth belt and/or at least one shaft. In this way, a slack-free torque transmission and thus a drive of the rotor shaft at both axial ends thereof which is synchronized with respect to the rotational frequency can be realized in a simple way.

In some embodiments, the geometrical axes of the driving shaft of the at least one motor and of the rotor shaft are identical. In this arrangement, the drive shaft of the motor and the rotor shaft can be connected rigidly or via a possibly flexible intermediate part or can even be manufactured as one piece, making further mechanical drive elements largely superfluous.

In some embodiments, the at least one motor has a hollow shaft, the stator of the motor being designed in a way integrated into the housing, or the motor being flanged to the housing supporting the rotor shaft. In both cases, a compact and stable arrangement of the motor and an equally compact and stable connection to the rotor shaft results.

The medium with a lower density than the density of the ambient air which medium the sealed space is filled with can be generated in different ways:

In some embodiments, this medium is air with a lower density than the density of the ambient air. This air can be generated by a vacuum pump which sucks air from the sealed space and thus generates a partial vacuum there. Even when taking the energy requirements of the vacuum pump into account, significant energy savings result altogether due to the reduced air resistance of the rotor bow, resulting in lower energy losses due to frictional heat.

However, the medium can also be a gas having a lower density than air at the same pressure and the same temperature. For example, helium is suitable for this purpose, which only has a density of about 0.1785 kg/m³, as opposed to air with a density of about 1.293 kg/m³, measured under normal conditions (0° C. and atmospheric pressure) in each case. For this purpose, for example also soiled helium is sufficient, which cannot be used for other technical processes, for instance in the semiconductor field, anymore and is thus available at a low price.

Of course, the two media can also be combined, i.e., a helium-air mixture can for example be used, or for example helium can additionally be dosed into a partial vacuum in the sealed space.

The sealed space can have differently large dimensions and can accordingly also enclose different numbers of components of the braiding machine:

In some embodiments, the sealed space substantially only extends around the rotor. In this way, the volume to be evacuated can be kept particularly small.

In some embodiments, the sealed space substantially extends around the complete braiding machine. Its enclosure can be substantially identical to the machine housing, the machine housing being sealed in an air-tight way. In this way, no obstacles result from the enclosure of the sealed space when loading and unloading the braiding machine.

Along with the advantages already mentioned like energy savings, lower noise development and lower vibrational excitation, the braiding machine according to some embodiments can also be operated at larger rotational frequencies and thus with larger feeding velocities of the strand-like material. For example, the lower vibrational excitation and thus the increased running smoothness of the rotor bow additionally result in an improved quality of the manufactured braid.

According to at least one of the disclosed embodiments, at least such air sealings with large diameters, or even such air sealings altogether, can be avoided.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a first embodiment of a braiding machine according to some embodiments with two motors arranged concentrically to the rotor shaft.

FIG. 2 is a second embodiment of a braiding machine according to some embodiments with one motor arranged concentrically to the rotor shaft and one motor arranged in parallel to the rotor shaft.

FIG. 3 is a third embodiment of a braiding machine according to some embodiments with one motor, which drives both axial ends of the rotor shaft.

FIG. 4 is a forth embodiment of a braiding machine according to some embodiments with one motor, which only drives one axial end of the rotor shaft.

FIG. 5 is a modification of the embodiment according to FIG. 4.

FIG. 6A and 6B respectively illustrate a conventional rotor bow and a rotor bow according to some embodiments in a developed view.

DETAILED DESCRIPTION OF CERTAIN INVENTIVE EMBODIMENTS

In a braiding machine according to some embodiments and according to FIG. 1 with a machine housing or machine stand 7, a plurality of wires are wound off one spool each (not shown) and are introduced into the machine at a wire infeed 12 into a central bore of a section 5 at the infeed side of a rotor shaft. The wires are running in the bore up to shortly before the other end of section 5 of the rotor shaft at the infeed side, where they are guided out of the rotor shaft through an opening and are guided onto a curved rotor bow 4 via a deflection roller 15. The braiding of the wires by twisting them with each other takes place, amongst others, in the axial bore of section 5 of the rotor shaft at the infeed side.

On the end at the infeed side of section 5 of the rotor shaft at the infeed side, furthermore an electric transmission unit 21 is arranged. This unit serves for transmitting electric energy onto the rotating components of the rotor, for example, for driving a winding spool (not shown). Here, the current transmission is established by contact rings with carbon brushes.

Rotor bow 4 rotates around the axis of rotor shafts 5, 6 and takes the braided wire with it, this wire being pressed to the inner side of rotor bow 4 by the centrifugal force and is, for example, guided through a guiding groove there and is fixed to rotor bow 4 by guiding elements in the form of eyelets (not shown). The opposite end of rotor bow 4 is supported on section 6 of the rotor shaft at the deflection side.

Each of the sections 5 and 6 or the rotor shaft is rotatably supported against a machine housing 7 by one or more bearings 20, for example, roller bearings. The two sections 5 and 6 of the rotor shaft are not rigidly, but only via the partially flexible rotor bow 4, connected to each other.

The braided wire is fed on the section 6 of the rotor shaft at the deflection side via a deflection roller 16, which is rotatably supported on the section 6 of the rotor shaft at the deflection side, to a winding spool (not shown). As soon as the winding spool is filled, the machine housing 7 is opened and the full winding spool is exchanged to an empty spool.

Furthermore, the whole wire braiding machine 1 can be arranged in a noise protection cabin (not shown).

The wire braiding machine 1 is a so-called double-twist braiding machine. The structure described so far of the wire braiding machine 1 is also present substantially in the same way with all embodiments described hereafter and is, as long as there are no changes in comparison to this structure, not described again there. In general it is also possible to apply the invention to braiding machines of other types. Furthermore, features of different example embodiments described in the following can of course—as long as technically feasible—be combined with each other.

Likewise, the rotor of the wire braiding machine 1, which rotor substantially has the sections 5 and 6 of the rotor shaft and the rotor bow 4, is arranged in a sealed space 2, in which a partial vacuum has been established by a vacuum pump (not shown), in all example embodiments described in the following.

As already described above, the reduced air friction between the rotor bow 4, which is rotating very fast, for instance at 4500 rotations per minute, and the remaining air in the sealed space 2 results in a reduced heat and noise development and a reduced vibrational excitation and thus in an increased running smoothness of the rotor bow 4. As also described above, the same advantages can also be achieved by dosing in a gas with a lower density than air like, for example, helium or a mixture of air and such a gas. Due to the lower noise development, one can possibly also completely do without the noise protection cabin mentioned.

In the example embodiment in FIG. 1, the section 5 at the infeed side and section 6 at the deflection side of the rotor shaft are driven by one individual motor 8 a, 8 b each, the stator units 9 a, 9 b of motors 8 a, 8 b being integrated into a machine housing 7 and the rotor units 10 a, 10 b of motors 8 a, 8 b being concentrically and rigidly connected to the respective section 5, 6 of the rotor shaft. The motors 8 a, 8 b are housing-integrated hollow shaft motors, into whose motor shafts the respective section 5, 6 of the rotor shaft can be pushed.

Alternatively, the motors 8 a, 8 b can be motors consisting of mounting kits, the stator units 9 a, 9 b and the rotor units 10 a, 10 b being delivered as separate components. In this case, the rotor units 10 a, 10 b are pushed onto the sections 5, 6 of the rotor shaft and are then mounted together with these sections in the machine housing 7 to the stator units 9 a, 9 b.

Because the sections 5, 6 of the rotor shaft, or the two motors 8 a, 8 b, respectively, are not mechanically coupled to each other, in this example embodiment the two motors 8 a, 8 b must be exactly synchronized with respect to their rotational frequencies, for example by common control electronics, in order to avoid an overload or even a damage of rotor bow 4 due to different rotational frequencies.

By deploying two separate motors 8 a, 8 b for the two sections 5, 6 of the rotor shaft, no additional mechanical components for the drive of the rotor shaft are necessary. For example, also the rotor shaft is arranged within the sealed space 2 with its sections of largest diameter, so that no air sealings with large diameters are necessary between the sealed space 2 and the environment at the lead-through points of the rotor shaft.

Only at the and at the infeed side of the section 5 at the infeed side of the rotor shaft, an air sealing 14 is provided, by which the lead-through point of this section 5 of the rotor shaft through the enclosure 3 of the sealed space 2 is sealed. An air sealing 14 has a fixed outer part and an inner part rotating along with the rotor shaft, the two parts contacting each other for the purpose of sealing. The section of the rotor shaft in the area of the air sealing 14, however, only serves for feeding the wire and can have a correspondingly small diameter. Thus, also the air sealing 14 only has a small diameter and generates correspondingly little friction heat.

Alternatively, it is also possible to completely do without the outermost section of the rotor shaft of smaller diameter, which is extending from the sealed space 2, and to let the rotor shaft end in the interior of the sealed space 2 at the point of the increase of the diameter thereof. In this case, the wires are introduced into sealed space 2 through a fixed drawing die and/or a ferrule and are only conveyed to the rotor shaft in the interior thereof, whereby one can completely do without the air sealing 14 with components which are moveable against each other. Here, the drawing die and/or the ferrule should have a length as long as possible, and at the same time the gap dimensions in the bore of the gap around the wire should be as small as possible.

In this way, the flow resistance for the air infiltrated into the gap becomes so high that the vacuum pump can compensate an increase of pressure in sealed space 2 by inflowing air entering through the “leak” caused by the ferrule.

Of course, a wire lead-through which is arranged fixedly relative to the environment and which is not rotating, as shown in FIG. 4, can be combined at wire infeed 13 with the machine embodiments according to FIGS. 1 to 3.

The wire braiding machine 1 according to some embodiments, as shown in FIG. 2, differs from the one shown in FIG. 1 only in the drive of the two rotor shaft sections 5, 6. Also in this case, the rotor shaft sections 5, 6 are driven by two separate motors 8 a, 8 b, which, however, are arranged as separate components, each one being encapsulated in an individual housing, in the sealed space 2 and are fixed at the machine housing or machine stand 7.

Here, the drive motor 8 b for the section 6 at the deflection side of the rotor shaft is flanged to the front side of the machine housing 7 at the deflection side in such a way that its shaft 11 b concentrically engages the section 6 of the rotor shaft at the deflection side with its front side. The drive motor 8 a for the section 5 of the rotor shaft at the infeed side, on the other hand, is fixed to the machine stand 7 in such a way that its shaft 11 a is oriented in substantially parallel to the rotor shaft. Torque transmission between the motor 8 a and the section 5 of the rotor shaft at the infeed side is accomplished by a tooth belt drive with two tooth belt disks 17 a and a tooth belt 18 a. Both of the motors 8 a and 8 b can be completely arranged within the sealed space 2. Also in this case, the two motors 8 a and 8 b can be exactly synchronized with respect to their rotational frequencies.

Also in this example embodiment, only one air sealing 14 of a smaller diameter is necessary at a wire infeed 12, which air sealing is even completely superfluous again when using a drawing die or a ferrule for feeding the wire.

Only one drive motor 8 is provided with the wire braiding machine 1 according to some embodiments as shown in FIG. 3. This drive motor 8 drives both of the section 5 at the infeed side and the section 6 at the deflection side of the rotor shaft via two tooth belt drives with two tooth belt sprockets 17 a, 17 b each and one tooth belt 18 a, 18 b each. Here, the arrangement of motor 8 and of the first tooth belt drive for the section 5 of the rotor shaft at the infeed side is substantially identical to the arrangement in FIG. 2. The second tooth belt drive for the section 6 of the rotor shaft at the deflection side is substantially arranged in a mirror symmetrical way with respect to a vertical central axis of the wire braiding machine 1. The second tooth belt drive and the motor 8 are connected by an intermediate shaft 19. This intermediate shaft is arranged in parallel to the rotor shaft and forms an extension of the shaft 11 of the motor 8. In this way, the two tooth belt drives and thus the two sections of the rotor shaft are running with the same rotational frequency.

Here, a sealed space 2 only extends around the two tooth belt drives, but not around motor 8 and intermediate shaft 19, whereby the volume of the sealed space 2 can be kept small. Thus, also the time and effort for manufacturing and sealing the enclosure 3 of the sealed space 2 is correspondingly small, and a low-power vacuum pump can be deployed.

In this example embodiment, two air sealings 14 are present at the lead-through points of shaft 11 of the motor 8 and of intermediate shaft 19 through enclosure 3 of sealed space 2. Due to the small diameters of both of the shafts 11 and 19, however, also air sealings 14 have small diameters. The sealing of the wire infeed 12 is again accomplished according to one of the possibilities described above.

In this example embodiment, the sealed space 2 can alternatively also be extended so widely that both of the motor 8 and intermediate shaft 19 are completely arranged therein (shown in dashed lines in FIG. 3). In this case, the two air sealings 14 can then completely be omitted.

In the wire braiding machine 1 according to some embodiments as shown in FIG. 4, again only a single drive motor for the rotor shaft is provided. This drive motor 8 is flanged to a machine stand 7 from outside the enclosure 3 of the sealed space 2. In this case, however, the motor 8 is encapsulated in an air-tight housing, so that the lead-through of the motor shaft 11 through the encasing 3 of the sealed space 2 need not be separately sealed. Similarly to FIGS. 2 and 3, the motor 8 drives the section 5 of the rotor shaft at the infeed side via a tooth belt drive with two tooth belt sprockets 17 and a tooth belt 18.

As opposed to the previous example embodiments, in the example embodiment according to FIG. 4 no section of the rotor shaft at the deflection side is provided at all, so that no drive at the deflection side must be provided either. Instead, a deflection roller 16 is just supported rotatably around the geometrical axis of the rotor shaft in a housing 22 by two bearings 23 a and 23 b, for example, two roller bearings, and is seized and put into rotation by a rotor bow 4, which is fixed to it. Here, the outer bearing 23 a serves for supporting rotor bow 4 housing 22 against rotor bow 4 machine housing 7, and rotor bow 4 inner bearing 23 b serves for supporting rotor bow 4 housing 22 against an intermediate part 24 between the housing 22 and the section 5 of the rotor shaft at the infeed side, which intermediate part is not rotating and is arranged coaxially to the rotor shaft. In other machine variants, for example a spool carrier in the interior of the rotor can be fixed to the intermediate part 24.

The design without a drive of the rotor at the deflection side thereof is substantially enabled by the fact that the rotor bow 4 can be designed with an enlarged cross-sectional area and thus more stably due to the partial vacuum in the sealed space 2, without the air resistance of the rotor bow 4 being substantially increased. For increasing the stability of the structure, also a second rotor bow can be provided which diametrically faces the first rotor bow 4 in the plane of rotation, whereby also a more uniform mass distribution and thus a smaller imbalance during the rotation of the rotor results.

By omitting the drive of the rotor at the deflection side thereof, a more compact and simpler design of wire braiding machine 1 with a substantially reduced number of mechanical components is reached. In this embodiment of wire braiding machine 1 as well, no air sealings with components contacting each other and moving against each other are necessary. The wire infeed 12 is again realized in one of the variants which were already described several times above. In FIG. 4 a wire infeed ferrule 13 is provided for this purpose, so that no such air sealing is necessary at the wire infeed 12 either.

FIG. 5 is a modification of the embodiment according to FIG. 4 in which the section 5 of the rotor shaft at the infeed side and the housing 22 for deflection roller 16 deflection roller 16 are connected to each other via two tooth belt drives with two tooth belt sprockets 17 a, 17 b each and one tooth belt 18 a, 18 b each and which are thus synchronized with respect to their rotational frequencies.

Insofar, the design resembles the tooth belt drives in the embodiment according to FIG. 3. Such a drive at both ends of the rotor shaft can make sense if the section 5 of the rotor shaft at the infeed side and the housing 22 have too much torsion against each other during the operation of braiding machine 1.

Finally, in FIGS. 6A and 6B, several rotor bows are shown in a developed view, i.e., the surface of the rotor bow has been cut along the longitudinal axis thereof and has been developed into the drawing plane.

FIG. 6A shows a conventional non-reinforced rotor bow having a constant width along its whole length, thus having a rectangle as its development.

FIG. 6B shows a reinforced rotor bow 4 for deployment in a wire braiding machine 1 according to the example embodiment in FIG. 4, whose axial ends are very much broadened. Here, the straight middle part 25 of the rotor bow 4 passes into the conical end pieces 25, the increase of the cross-sectional area of the rotor bow 4 at the end pieces 25 being clearly visible from the much extended vertical outer edges in the developed view. In this way, the rotor bow 4 gets substantially more torsion-resistant and provides a particularly stiff connection to the housing 22 for the deflection roller 15 in order to seize this housing during its rotation.

Here, the development can also have other contours leading to a particularly advantageous development of stress-resultant forces and/or stress-resultant moments according to stability calculation.

While the inventive technology has been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope as defined by the following claims. 

What is claimed is:
 1. A braiding or stranding machine for braiding or stranding a strand-like material, the machine comprising: a rotor with a one-part or a multi-part rotor shaft which is driven by at least one motor, the braiding or stranding machine being at least partially arranged in a sealed space which is filled with a medium with a lower density than the density of the ambient air, wherein the rotor shaft is completely arranged within an enclosure of the sealed space or wherein the rotor shaft has at least one section of a smaller diameter and at least one section of a larger diameter and penetrates the enclosure of the sealed space only in the at least one section of the smaller diameter.
 2. The machine according to claim 1, wherein the rotor shaft does not penetrate the enclosure of the sealed space in the at least one section of the larger diameter.
 3. The machine according to claim 1, wherein the braiding or stranding machine does not have sealings for sealing the sealed space against the environment with parts that contact each other and rotate against each other.
 4. The machine according to claim 1, wherein the rotor is rotationally driven only at one axial end of the rotor.
 5. The machine according to claim 4, wherein the rotor has at least one rotor bow which is reinforced in the area of at least one of its axial ends in relation to its middle part by an increase of its cross-sectional area.
 6. The machine according to claim 4, wherein the rotor has at least two rotor bows.
 7. The machine according to claim 1, wherein the rotor shaft is driven at both axial ends of the rotor by one motor each.
 8. The machine according to claim 1, wherein the rotor shaft is driven by exactly one motor, the motor being coupled with the two axial ends of the rotor by mechanical torque transmission means and the drive acting on both axial ends of the rotor shaft, and the mechanical torque transmission means being completely or partially arranged within the sealed space.
 9. The machine according to claim 8, wherein the mechanical torque transmission means have at least one tooth belt and/or at least one shaft.
 10. The machine according to claim 1, wherein the geometrical axes of the driving shaft of the at least one motor and of the rotor shaft are identical.
 11. The machine according to claim 10, wherein the at least one motor has a hollow shaft or is flanged to the housing which supports the rotor shaft.
 12. The machine according to claim 1, wherein the medium is air with a lower density than the density of the ambient air.
 13. The machine according to claim 1, wherein the medium is a gas which has a lower density than air at the same pressure and the same temperature.
 14. The machine according to claim 13, wherein the gas is helium or a helium-air mixture.
 15. The machine according to claim 1, wherein the sealed space substantially only extends around the rotor.
 16. The machine according to claim 1, wherein the sealed space substantially extends around the whole braiding or stranding machine. 